From an unused root meaning apparently to contain; a receptacle (for milk, i.e. Pail; figuratively, breast) -- breast.
H5845. atin
[עֲטִין] noun [masculine] probably pail, bucket (Late Hebrew מַעֲטָן vessel for olives); — חָלָב מָֽלְאוּ עֲטִינָיו Job 21:24 his pails are full of milk.